Vocative

A vocative expression is an expression of direct address, wherein the identity of the party being spoken to is set forth expressly within a sentence. For example, in the sentence, "I don't know, John.", John is a vocative expression indicating the party who is being addressed.

Some languages (e.g., Greek) have a special vocative case for this; others do not. English simply uses the subjective case for vocative expressions but sets them off from the rest of the sentences with pauses (rendered in writing as commas).

A vocative expression is interjective and can occur in any clause, irrespective of mood. Some examples...

• Good morning, class!
• Don't forget your swimming trunks, George.
• Hey, George, did you remember to bring your swimming trunks?
• No, Bob, I forgot.
• I'm proud of you, son.
• If I were you, Mary, I'd take French next year instead of Spanish.